1. Field of the Invention
The present invention relates to devices for collecting sheets of material into a set, and more particularly, to devices for collecting sheets of paper in sets and conveying them to a subsequent station.
2. Prior Art
Duplicating machines are becoming increasingly sophisticated and many types are capable of performing additional operations on sheets of paper once they have been duplicated by the duplicator. For example, duplicators may include a device which receives a set of sheets and binds it together to form a pamphlet. Since the sheets bound to form the pamphlet are duplicated serially, it is necessary to collect the sheets from the duplicating portion of the machine into a set, then transport the set in a manner that minimizes skewing of the sheets to a station where they can be bound or otherwise processsed.
There are many devices now used for collecting the output of the duplicating portion of a duplicating machine. One example is disclosed in U.S. Pat. No. 3,972,525 which is directed to a sheet stacking assembly which includes a reciprocating jogging finger extending above a substantially horizontal plate across which the duplicated sheets travel. The sheets are propelled across the plate by the momentum they receive from sliding down an inclined plane and by a roller protruding from the plate ahead of the jogging finger. The sheets pass over the reciprocating jogging finger which then urges them toward a stop. After the sheets have been collected against the stop, they can be processed further and bound by means such as a stapling device.
After the sheets have been stacked against the stop and bound, the stop is lowered into the surface of the table and a pair of pinch rollers engage the bound set to drive it onto a subsequent station. A disadvantage of this system is that the action of the reciprocating jogging finger as well as a roller which protrudes above the floor of the supporting surface may cause the sheets to float and become arranged in a skewed position with respect to each other.
Another example is disclosed in U.S. Pat. No. 3,719,266, which is directed to a stacking device which utilizes a gravity feed. Sheets are fed serially through pinch rollers and downwardly between baffles to a gate. The sheets rest vertically against the gate as they are being collected into a set. A disadvantage of this device is that it requires additional powered components such as paddle wheels to arrange the sheets into a set.
Accordingly, there is a need for an accumulator which can collect sheets into a set in a manner that minimizes the possibility of the sheets becoming skewed with respect to one another. In addition, there is a need for an accumulator which can transport a set of collected sheets to a finishing station with a minimum amount of skewing of the individual sheets. Furthermore, such an accumulator should have a simplified construction and should be adjustable to collect and transport sets of sheets having varying thicknesses.